Blister-type packages are popular for storing and displaying articles for sale. The two primary components of a blister pack are the cavity or pocket made from a formable material (e.g., plastic) and a lid (e.g., paperboard or plastic). The formed cavity or pocket contains the product and the lid seals the product within the cavity. Other types of blister packs may consist of carded packages where the products are contained between a paperboard card and clear pre-formed plastic (e.g., polyvinylchloride). The consumer can easily examine the product through the transparent plastic. The plastic shell is vacuum-formed around a mold so it can contain the item snugly. The card may be brightly colored and designed depending on the item inside, and the pre-formed plastic is affixed to the card using heat and pressure to activate an adhesive (heat seal coating) on the blister card. The adhesive is strong enough so that the pack may hang on a peg, but weak enough so that the package can be easily opened. The card may also have a perforated window for access. A more secure package is known as a clamshell. It is often used to deter package pilferage for small high-value items such as consumer electronics. It consists of either two pre-formed plastic sheets or one sheet folded over onto itself and fused at the edges. They are usually designed to be difficult to open by hand so as to deter tampering. A pair of scissors or a sharp knife is often required to open them. Care must be used to safely open some of these packages.
Blister packs are typically thermoformed. Thermoforming is a manufacturing process where a plastic sheet is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a usable product. The sheet (or film when referring to thinner gauges and certain material types), is heated in an oven to a high-enough temperature that it can be stretched into or onto a mold and cooled to a finished shape. For high-volume applications, very large production machines are utilized to heat and form the plastic sheet and trim the formed parts from the sheet in a continuous high-speed process, and can produce many thousands of finished parts per hour depending on the machine and mold size and the size of the parts being formed.
Consumers have been demanding environmentally friendly changes in consumer product packaging, such as minimizing the use of plastic and other non renewable materials. Many consumers are concerned about the environmental impact of packaging. Researchers believe that global green initiatives have strongly influenced this consumer attitude. Researchers also believe this new consumer attitude that will continue to push packaging manufacturers into finding environmentally friendly packaging alternatives. Typical plastics take an extended period of time to compost (break down) in landfills. New environmentally friendly packaging materials are made from renewable materials that can be grown quickly (unlike most trees). Renewable materials may be recyclable and/or biodegradable. Several alternatives to plastics have been developed for thermoforming blister packs and trays, such as, paper board and renewable plant fiber. Despite the environmental advantages of these materials, current manufacturing processes (e.g., thermoforming) often limit the design and functionality of the final package. For example, the blister pack may require multiple angled sides because of draft angle requirements in order to remove the pack from a mold or tool during manufacturing. In another example, fiber trays with multiple draft angles and/or reverse draft foot areas are difficult to automatically feed on automated packaging machines, inter alia, because the surface energy of a fiber tray tends to stick the trays together as the walls of the fiber tray touch during stacking, thus, making it difficult to denest the trays. What is needed, then, is an environmentally friendly package that is cost-effective, easier and faster to manufacture, and/or easier and faster to assemble with more precision.